code: def test_buffer(method):
      # Smoke test that sparse matrices with read-only buffers (e.g., those from
      # joblib workers) do not cause::
      #
      #     ValueError: buffer source array is read-only
      #
      G = scipy.sparse.csr_matrix([[1.0]])
      G.data.flags["WRITEABLE"] = False
      shortest_path(G, method=method)
  
imports: from io import StringIO
  import warnings
  import numpy
  from numpy.testing import assert_array_almost_equal, assert_array_equal, assert_allclose
  from pytest import raises
  from scipy.sparse.csgraph import shortest_path, dijkstra, johnson, bellman_ford, construct_dist_matrix, NegativeCycleError
  import scipy.sparse
  from scipy.io import mmread
  import pytest
label_desc: Use image node_id 18 for calling a global function with example usage: test_buffer(method) without return types